1. Field of the Invention
The present invention relates to a vehicle turn control system which performs turn control of a vehicle by yaw moment control.
2. Description of the Related Art
According to a known technique for turn control of a vehicle, the turning of a vehicle is controlled by controlling the yaw moment so as to minimize the deviation of the real yaw rate from the lateral G-derived yaw rate, which is calculated on the basis of the lateral acceleration and the speed of the vehicle.
For example, Japanese Patent Laid-Open No. 2005-153716 (which is hereinafter referred to as JP2005-153716A) discloses a brake control system including a brake control unit, a steering-condition detection unit, and a yaw-moment imparting unit. The brake control unit performs deceleration control of the vehicle in which the brake control system is installed, so as to assist the driver in deceleration in accordance with the intention of the driver. The steering-condition detection unit detects at least one of the steering angular velocity and the steering angular acceleration. While the brake control unit is controlling deceleration of the vehicle, the yaw-moment imparting unit imparts a yaw moment to the vehicle on the basis of the at least one of the steering angular velocity and the steering angular acceleration which is detected by the steering-condition detection unit. The yaw moment imparted by the yaw-moment imparting unit increases with the magnitude of the deceleration of the vehicle controlled by the brake control unit.
The brake operating unit according to JP2005-153716A can appropriately control the yaw moment so as to improve the turnability of the vehicle.
However, in the brake operating unit according to JP2005-153716A, if the driver performs a manipulation for braking while the yaw moment control by use of a hydraulic system is performed, brake control by use of the hydraulic system is also performed on wheels which are not to be subject to the yaw moment control. Therefore, there is a possibility that the driver feels a sense of incongruity (e.g., a rattle of the brake pedal) accompanied by the manipulation for braking.
In view of above, the object of the present invention is to provide a vehicle turn control system which can cause the driver to feel comfortable without feeling a sense of incongruity even when the driver performs a manipulation for braking during yaw moment control.